Experimental investigation of mechanical, hydration, microstructure and electrical properties of cemented paste backfill

•The uniaxial compressive strength of CPB was studied.•The Weibull average compressive strength of the backfill was analyzed.•The relationship between hydration products and strength was established.•The microstructure of CPB was analyzed by SEM-EDS. Filling mine goafs with cemented paste backfill (CPB) is an effective approach to protect the ecological environment and alleviate major safety hazards in practice. In this study, using full tailings of the Xianglushan Tungsten Mine as experimental materials, the relationship between compressive strength, hydration products, microstructure, and electrical resistance (ER) of CPB was investigated through macro and micro characterization at different curing times. The results show that under standard curing conditions, the uniaxial compressive strength (UCS) of CPB was the highest at 28d with the tailing to cement ratio (T/C) of 4 and the concentration of 72%. The Weibull average compressive strength was (1.058 ± 0.064) MPa. The mineral composition and chemical types of CPB hydration products at different backfill curing times were quantitatively analyzed using X-ray diffraction (XRD) and standard powder diffraction (PDF) data. Further, the quantitative relationship between hydration product content and strength of backfill was established. The evolution of microstructure, pore characteristics, and electrical characteristics of CPB was investigated by scanning electron microscopy-energy dispersive spectroscopy, nuclear magnetic resonance, and inductance-capacitanceresistance testing (LCR). The results of this work would be helpful for the analysis of strength characteristics and hydration product properties of CPB.